Americans vote in an election of rare historic potential Tuesday, with front-running Democrat Barack Obama seeking to become the first black president and Republican John McCain hoping for a poll-defying comeback.

After an epic campaign, voters could also spark a political realignment in Washington, with Democrats targeting big gains in the Senate and House of Representatives after eight turbulent years under President George W. Bush.

History’s longest, most costly White House campaign ends with Democrat Obama the hot favorite , with wide leads in national polls and the edge in a string of battleground states which could swing the election either way.

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In the eye of the worst financial storm since the 1930s and with US troops embroiled in wars in Iraq and Afghanistan, both Obama and McCain have vowed to restore the frayed self-confidence of the world’s lone superpower.

Obama and McCain will be chasing the 270 electoral votes needed across the diverse state-by-state electoral map to take the White House. More than 100 million people are expected to trek to the polls to add to 30 million advance votes already cast.

A d v e r t i s e m e n t

The tiny New Hampshire towns of Dixville Notch and Hart’s Location played their traditional role of hosting the first election day voting just after midnight (0500 GMT). Obama won a majority of votes in both places.